Preparation of the soil comprises a very important part of a farming operation. Although natural factors are the ultimate determinants, the soil must be properly prepared in order for the planting to be successful. The soil or land is usually prepared in two stages. First, a plow is utilized to cut, lift and turn over the soil. However, plowing leaves a field in a relatively coarse condition which may be unsuitable for the seeding of some crops. Harrowing comprises the second typical stage of soil preparation. A disc harrow is utilized to further pulverize the soil and leave the field in a relatively smooth and level condition for planting.
A popular type of field harrow is the tandem disc harrow, which comprises front and rear pairs of disc gangs. The prior art includes several examples of such tandem disc harrows, many having the common disadvantage of leaving an uncut center balk of unharrowed zone with each pass of the implement. Some of the disc harrows of the prior art are either unadjustable or only adjustable with considerable difficulty. In addition, some of the prior disc harrows have tended to be of unnecessarily complex construction requiring more maintenance and resulting in greater expense. Heretofore, disc harrows suitable for field use have been of the pull type only and have thus been difficult to control and maneuver when drawn by a tractor. There is thus a need for an improved disc harrow of the tandem type which effects harrowing and leveling across the entire width thereof without leaving a center balk.